Please wait, while we are loading the content...
Please wait, while we are loading the content...
| Content Provider | Springer Nature Link |
|---|---|
| Author | Dales, H. G. Feinstein, J. F. |
| Copyright Year | 2010 |
| Abstract | We investigate the completeness and completions of the normed algebras (D $^{(1)}$(X), ‖ · ‖) for perfect, compact plane sets X. In particular, we construct a radially self-absorbing, compact plane set X such that the normed algebra (D $^{(1)}$(X), ‖ · ‖) is not complete. This solves a question of Bland and Feinstein. We also prove that there are several classes of connected, compact plane sets X for which the completeness of (D $^{(1)}$(X), ‖ · ‖) is equivalent to the pointwise regularity of X. For example, this is true for all rectifiably connected, polynomially convex, compact plane sets with empty interior, for all star-shaped, compact plane sets, and for all Jordan arcs in ℂ.In an earlier paper of Bland and Feinstein, the notion of an $$ \mathcal{F} $$ -derivative of a function was introduced, where $$ \mathcal{F} $$ is a suitable set of rectifiable paths, and with it a new family of Banach algebras $$ D_\mathcal{F}^{\left( 1 \right)} \left( X \right) $$ corresponding to the normed algebras D $^{(1)}$(X). In the present paper, we obtain stronger results concerning the questions when D $^{(1)}$(X) and $$ D_\mathcal{F}^{\left( 1 \right)} \left( X \right) $$ are equal, and when the former is dense in the latter. In particular, we show that equality holds whenever X is ‘ $$ \mathcal{F} $$ -regular’.An example of Bishop shows that the completion of (D $^{(1)}$(X), ‖ · ‖) need not be semisimple. We show that the completion of (D $^{(1)}$(X), ‖ · ‖) is semisimple whenever the union of all the rectifiable Jordan arcs in X is dense in X.We prove that the character space of D $^{(1)}$(X) is equal to X for all perfect, compact plane sets X, whether or not (D $^{(1)}$(X), ‖ · ‖) is complete. In particular, characters on the normed algebras (D $^{(1)}$(X), ‖ · ‖) are automatically continuous. |
| Starting Page | 153 |
| Ending Page | 187 |
| Page Count | 35 |
| File Format | |
| ISSN | 00195588 |
| Journal | Indian Journal of Pure and Applied Mathematics |
| Volume Number | 41 |
| Issue Number | 1 |
| e-ISSN | 09757465 |
| Language | English |
| Publisher | Springer-Verlag |
| Publisher Date | 2010-04-11 |
| Publisher Place | India |
| Access Restriction | One Nation One Subscription (ONOS) |
| Subject Keyword | Normed algebra differentiable functions Banach function algebra completions pointwise regularity of compact plane sets Numerical Analysis Applications of Mathematics Mathematics |
| Content Type | Text |
| Resource Type | Article |
| Subject | Applied Mathematics |
National Digital Library of India (NDLI) is a virtual repository of learning resources which is not just a repository with search/browse facilities but provides a host of services for the learner community. It is sponsored and mentored by Ministry of Education, Government of India, through its National Mission on Education through Information and Communication Technology (NMEICT). Filtered and federated searching is employed to facilitate focused searching so that learners can find the right resource with least effort and in minimum time. NDLI provides user group-specific services such as Examination Preparatory for School and College students and job aspirants. Services for Researchers and general learners are also provided. NDLI is designed to hold content of any language and provides interface support for 10 most widely used Indian languages. It is built to provide support for all academic levels including researchers and life-long learners, all disciplines, all popular forms of access devices and differently-abled learners. It is designed to enable people to learn and prepare from best practices from all over the world and to facilitate researchers to perform inter-linked exploration from multiple sources. It is developed, operated and maintained from Indian Institute of Technology Kharagpur.
Learn more about this project from here.
NDLI is a conglomeration of freely available or institutionally contributed or donated or publisher managed contents. Almost all these contents are hosted and accessed from respective sources. The responsibility for authenticity, relevance, completeness, accuracy, reliability and suitability of these contents rests with the respective organization and NDLI has no responsibility or liability for these. Every effort is made to keep the NDLI portal up and running smoothly unless there are some unavoidable technical issues.
Ministry of Education, through its National Mission on Education through Information and Communication Technology (NMEICT), has sponsored and funded the National Digital Library of India (NDLI) project.
| Sl. | Authority | Responsibilities | Communication Details |
|---|---|---|---|
| 1 | Ministry of Education (GoI), Department of Higher Education |
Sanctioning Authority | https://www.education.gov.in/ict-initiatives |
| 2 | Indian Institute of Technology Kharagpur | Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project | https://www.iitkgp.ac.in |
| 3 | National Digital Library of India Office, Indian Institute of Technology Kharagpur | The administrative and infrastructural headquarters of the project | Dr. B. Sutradhar bsutra@ndl.gov.in |
| 4 | Project PI / Joint PI | Principal Investigator and Joint Principal Investigators of the project |
Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon |
| 5 | Website/Portal (Helpdesk) | Queries regarding NDLI and its services | support@ndl.gov.in |
| 6 | Contents and Copyright Issues | Queries related to content curation and copyright issues | content@ndl.gov.in |
| 7 | National Digital Library of India Club (NDLI Club) | Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach | clubsupport@ndl.gov.in |
| 8 | Digital Preservation Centre (DPC) | Assistance with digitizing and archiving copyright-free printed books | dpc@ndl.gov.in |
| 9 | IDR Setup or Support | Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops | idr@ndl.gov.in |
|
Loading...
|